Safety control system for gaseous fuel burners



Feb. 20, 1951 w. D. HALL SAFETY common SYSTEM FOR GASEOUS FUEL BURNERS Filed 001;. 20, 1944 Patented Feb. 20, 1951 SAFETY CONTROL SYSTEM FOR GASEOUS FUEL BURNERS William D. Hall, Elkins, W. Va.

Application October 20, 1944, Serial No. 559,568

8 Claims. (Cl. 158--117.1)

This invention relates to heaters, and has for its primary object the safe operation of the burner in event'of temporary cessation of the fuel supply. Other objects will appear as this description proceeds.

In fuel burning heaters, gaseous or liquid, there may be an escape of fuel for a short period in event the fuel is cut off and promptly reestablished. Devices have been provided to shut off the burner in event of such circumstances, but they have a time lag in doing so. According to this invention, I employ, in addition to such a device for closing the fuel valve within a time period after the flame goes out, a gas port that will remain ignited for a time period longer than the time required for the fuel valve to be closed as aforesaid. Hence, if the fuel supply resumes before the valve is closed, it will be relighted.

In the drawings, Figure 1 is a plan view of the invention. Figure 2 is an end view of Figure 1. Figure 3 is a sectional view of one of the hold over means of the invention.

In Figure 1 is shown a gas burner 68 having a plurality of jet openings 61, and also having a conventional mixer l2 for mixing the gas fuel with air. The burner is controlled by a control system 5 of Figure 2. This control system is the same as that shown in Figure 5 of my United States Patent No. 2,159,658, May 23, 1939, and parts SS, RT, and all parts the reference numbers are higher than 60 are identical with correspondingly numbered parts of Figure 5 of said prior patent. Metallic supports II and 18 are preferably composed of stainless steel and may be mounted on a fixed base. Slidably supported by the supports H and 18 are bars H and TI which may also be composed of some form of stainless steel. The bars 14 and 11 are not rigidly fastened to supports H and 18 but are arranged to slide through these supports. Hence, the bars will move when the bimetallic strips exert a force on them. The lower ends of bimetallic strips 66 and 19 are fixed and their upper ends move to the right when heated. Mounted on bar 14 is an insulating arm 66 and a metallic arm 69. Mounted on bar I1 is a metallic arm 15 and an arm 16 of insulation material. When strip 66 engages metallic arm 69 it closes a circuit to the conventional solenoid valve 12 causing the latter to open and allow gas to flow to the burner. When strip 19 is in contact with metallic arm 15 the igniter 62 is energized. The igniter 62 may ignite the fuel through the medium of a conventional flasher 6 l. Heater 63, which is in series with igniter 62, is arranged to heat bimetallic strip 66. A room thermostat RT and a safety switch SS (hereinafter described) are in series with the incoming line. Briefly speaking, the

operation of the control system will be referred to as follows. When room thermostat RT closes current flows through the following path, room thermostat RT, safety switch SS, resistor 63, lgniting coil 62, bimetallic strip 19, contact arm 15, sliding member ll, support 18 to the line. Heat from 63 heats bimetallic strip 66 and moves the same from insulated arm 68 to conducting metal arm 69 closing a circuit as follows: room thermostat RT, safety switch SS, solenoid valve 12, strip 66, metallic arm 69, sliding member 14, support ll to line. Flow of current in this circuit opens valve 12 causing gas to flow to burner 88 and into flasher 6|. The gas admitted to burner 88 through valve 12 is ignited by incan descent heater wire coil 62. The system has a safety switch SS which is of the same construction as the safety switch SS of my said prior patent. Should the coil 62 fall to ignite the gas, after a predetermined time, the safety switch SS will open the circuit and thereby close valve 12.

If fuel satisfactorily ignites and burns for a period of time, the bimetallic strip 19 will bend away from metallic arm 15 and break the circuit to the igniting coil 62. The heat from the flame will also heat bimetallic strip 66 and it will push the sliding member 14 through the stationary support ll, being retarded to some extent by friction. If the fuel supply from the gas house ceases for a short period, the strip 66 cools and moves away from arm 69 breaking the circuit to valve 12 closing the valve; however, it is noted that this operation requires a time interval of as much as 40 seconds, depending on the design of the control system. Usually the time is less. If the gas goes off after burning continuously and is then turned on after only a few seconds, there would (except for the present invention) be an escape of gas for the time required for the valve 12 to close. With most burners this escape of gas is in no way objectionable, but in other cases. for example tightly enclosed ovens, it may be. The

purpose of the present invention is to avoid the above objection.

The present invention is not limited in its application to use with the particular control system of my said prior patent, but has application to other types of control systems.

The present invention provides for means that remains at igniting temperature during the time required for the valve 'l2 to be closed upon cessation of the gas. Two ways of doing this are shown in the drawing either of which can be used independently of the other or both may be used together.

A device for accomplishing the function is that one or more of the ports iii of the burner 88 may be greatl enlarged. The remaining ports 81 are so small that normally when the gas goes out and the pressure in the burner is reduced, gas is no longer forced out of the remaining ports 81 due to their small size, but there is enough convection to carry the gas stored in the burner out of large port it and a small flame will burn at port ii for many seconds, ten or fifteen for example. Preferably, the design should be such that port 16 will remain ignited for as long after the others as possible and substantially as long as or longer than the time required for strip 66 to cool and close the valve.

Another way of accomplishing the invention is by use of a very small branch pipe H having a large chamber 10 that in turn has a large port 13 that is adjacent the burner. The gas will be stored in chamber I and will keep a flame burning at I3 for a substantial time after the flame goes out at ports 81. The speed of switch 66-53 should preferably be fast enoughto open before th'fiame at 13 goes out.

It is not necessary that the supplemental flame burn as long as the cooling time of the switch 66 to fall within the broadest aspects of my invention. A shorter time will be of some advantage.

I claim to have invented:

1. In a heating system, a burner, and means for permitting flow of fuel to the burns-r and for preventing said flow, a thermal element for operating said means to prevent fuel flow within a predetermined time after the flame goes out; said burner having a plurality of ports of such size that the flame dies out therefrom quickly upon a cessation of fuel flow and a port of much larger size than the first-named ports which will supply fuel for a small flame for at least ten seconds after cessation of fuel flow to the burner, said last-named port being sufficiently close to the first-named ones that its flame will ignite fuel from the first-named ports.

2. In a heating system, a burner defining a chamber and a plurality of closely spaced burner ports in a wall of the burner, one of said ports being considerably larger than the others and fed by the chamber common to all of the ports whereby it is subjected to the same chamber pressure and due to its larger size will support a name after cessation of gas supply for an extended period, a fuel feed line to said burner, and thermal means responsive to fall in temperature of the burner for closing said fuel line in a. time period less than said extended period.

3. The device of claim 2 in which said thermal means is a slip-friction type of thermostatic device which operates to close said fuel line upon change from a rising to a falling temperature.

4. In a heating system, a burner, control means subject to heat from the burner for admitting fuel thereto when the temperature of the burner is increasing and for stopping such flow within a limited time period after the temperature of the burner changes from a rising temperature to a falling one, and ignition means in igniting relation with the burner which is operable to ignite fuel from the burner for a limited time following cessation of fuel at the burner, the aforesaid limited time of operation of the ignition means being longer than the aforesaid limited time within which the control means will stop fuel flow, said burner defining a plurality of gas ports in igniting relationship with each other, and said ignition means including a port that is larger than the others and therefore remains ignited for a limited period after aefiame at the others dies out.

5. In a heating system, fuel burning means comprising a burner havin a main chamber and an auxiliary chamber, said fuel burning means including means to supply gas to both of said chambers, said main chamber defining a large number of burner ports in igniting relationship to each other, said auxiliary chamber defining a port in igniting relationship with one of those of the main burner, the last-named port being of sufficient size and the auxiliary chamber of sufficient capacity and being so constructed and arranged that the last-named port will remain ignited longer than those of the main burner when gas ceases to how to said chambers, and thermal means responsive to fall in temperature of the burner for stopping flow of gas to said burner.

6. The heating system defined in claim 1 having in addition, an electrical igniter for the burner, said means including means for energizing the igniter and restarting the flow of fuel after said thermal element has operated said first-named means to prevent flow of fuel.

7. The heating system defined in claim 2 having in addition, an electrical igniter for the burner, and means for deenergizing said igniter when the burner heats and for energizing the igniter when the burner cools.

8. The system defined in claim 4 including in addition, an electrical igniter for the burner, said control means including means for starting both the igniter and fuel flow during the starting period of the burner and for reenergizing the igniter and admitting fuel to the burner after the expiration of said limited time.

WILLIAM D. HALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 416,979 Williams Dec. 10, 1889 1,289,992 Willson Dec. 31, 1918 1,392,948 Kraus Oct. 11, 1921 1,394,807 Blanchard Oct. 25, 1921 1,429,521 Miller Sept. 19, 1922 1,475,644 Mershon Nov. 27, 1923 1,574,545 Bear Feb. 23, 1926 1,715,989 Calvert June 4, 1929 1,763,295 Englund June 10, 1930 1,853,444 McCabe Apr. 12, 1932 1,876,495 Gioe Sept. 6, 1932 1,898,799 Wetherbee Feb. 21, 1933 1,900,217 Adams Mar. 7, 1933 1,953,661 Svaicer Apr. 3, 1934 1,957,207 Harrington May 1, 1934 1,967,606 Brown July 24, 1934 1,985,991 Harrington Jan. 1, 1935 2,077,297 Williams Apr. 13, 1937 2,098,383 Furlong Nov. 9, 1937 2,133,103 Le Ferre Oct. 11, 1938 2,135,275 Cannon Nov. 1, 1938 2,148,797 Barna Feb. 28, 1939 2,159,658 Hall May 23, 1939 2,177,114 McCollum et a1. Oct. 24, 1939 2,286,156 Petersen June 9, 1942 2,291,805 Denison Aug. 4, 1942 2,352,329 Koppel June 27, 1944 FOREIGN PATENTS Number Country Date 627,024 Germany Mar. 6, 1936 

